U.S. patent application number 14/579476 was filed with the patent office on 2015-07-09 for touch pad with antenna.
The applicant listed for this patent is ALPS ELECTRIC CO., LTD.. Invention is credited to Takeshi Masaki, Takahiro Murakami, Hiroaki Takahashi.
Application Number | 20150193080 14/579476 |
Document ID | / |
Family ID | 53495155 |
Filed Date | 2015-07-09 |
United States Patent
Application |
20150193080 |
Kind Code |
A1 |
Takahashi; Hiroaki ; et
al. |
July 9, 2015 |
TOUCH PAD WITH ANTENNA
Abstract
A touch pad with an antenna includes a substrate on an upper
side of which an operation surface having a predetermined operation
region is set, an electrode group for detecting capacitance
configured to be arranged in a region of the substrate
corresponding to the operation region, and an antenna for wireless
communication configured to be arranged in a region located on a
lower side of the substrate, the region overlapping with an
electrode forming region in which the electrode group for detecting
capacitance is formed, as viewed from above. The electrode group
for detecting capacitance includes a first electrode group extended
in a predetermined first direction and a second electrode group
extended in a second direction perpendicular to the first
direction, and the antenna is extended in a direction intersecting
with the first direction and the second direction.
Inventors: |
Takahashi; Hiroaki;
(Miyagi-ken, JP) ; Murakami; Takahiro;
(Miyagi-ken, JP) ; Masaki; Takeshi; (Miyagi-ken,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ALPS ELECTRIC CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
53495155 |
Appl. No.: |
14/579476 |
Filed: |
December 22, 2014 |
Current U.S.
Class: |
345/174 |
Current CPC
Class: |
G06F 3/03547 20130101;
H01Q 1/48 20130101; H01Q 7/00 20130101; G06F 3/0445 20190501; G06F
3/0446 20190501; H01Q 1/2266 20130101; G06F 1/169 20130101; G06F
2203/0384 20130101; G06F 3/0227 20130101; H01Q 1/44 20130101 |
International
Class: |
G06F 3/041 20060101
G06F003/041; H01Q 1/48 20060101 H01Q001/48; H01Q 1/22 20060101
H01Q001/22; G06F 3/044 20060101 G06F003/044; H01Q 7/00 20060101
H01Q007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 7, 2014 |
JP |
2014-001163 |
Claims
1. A touch pad with an antenna comprising: a substrate on an upper
side of having set thereon an operation surface having a
predetermined operation region; an electrode group that detects
capacitance arranged in a region of the substrate corresponding to
the operation region; and an antenna for wireless communication
arranged in a region located on a lower side of the substrate, the
region overlapping with an electrode group forming region in which
the electrode group for detecting capacitance is disposed, as
viewed from above, wherein the electrode group for detecting
capacitance includes a first electrode group extended in a
predetermined first direction and a second electrode group extended
in a second direction perpendicular to the first direction, and
wherein the antenna is extended in a direction intersecting with
the first direction and the second direction.
2. The touch pad with an antenna according to claim 1, wherein the
antenna comprises a coiled antenna wound along an outer
circumference of a circle.
3. The touch pad with an antenna according to claim 1, wherein the
operation region is a rectangular-shaped region having a long side
extending in the first direction and a short side extending in the
second direction, and the antenna comprises a coiled antenna wound
along an outer circumference of an ellipse having a long axis
extending in the first direction and a short axis extending in the
second direction.
4. The touch pad with an antenna according to claim 1, wherein a
ground electrode made of a conductive material is arranged at a
position, located on a lower side of the electrode group for
detecting capacitance and located on an upper side of the antenna,
so as to overlap with a whole region of the electrode forming
region as viewed from above, and a plurality of slits are formed in
the ground electrode so as to radially extend from the vicinity of
a central portion of the ground electrode.
5. The touch pad with an antenna according to claim 4, wherein the
slits are arranged at regular intervals with respect to a rotation
direction centered at the central portion of the ground
electrode.
6. The touch pad with an antenna according to claim 4, wherein the
slits are formed so as to divide an outer periphery portion of the
ground electrode.
7. The touch pad with an antenna according to claim 4, wherein the
ground electrode includes a linking portion configured to link a
plurality of ground electrode patterns divided by the slits, in the
central portion of the ground electrode.
Description
CLAIM OF PRIORITY
[0001] This application claims benefit of Japanese Patent
Application No. 2014-001163 filed on Jan. 7, 2014, which is hereby
incorporated by reference in its entirety.
BACKGROUND
[0002] 1. Field of the Disclosure
[0003] The present disclosure relates to a touch pad with an
antenna, and in particular, relates to a touch pad with an antenna,
used for wireless communication.
[0004] 2. Description of the Related Art
[0005] Touch pads in each of which the position of an operation
body in contact with or close to an operation surface is detectable
have become very popular, and have been used for moving cursors of
screens of electronic devices such as notebook computers. The touch
pads are each attached to an opening portion formed in a
predetermined location (a palm rest or the like) of a chassis
covering the main body of an electronic device such as a notebook
computer.
[0006] The opening portion to which the touch pad is attached is
used for radiating, to the outside of the electronic device, a
wireless signal (electromagnetic wave signal) generated by a
communication circuit on an electronic device side. In addition, in
recent years, touch pads with antennas, in each of which an antenna
for wireless communication connected to such a communication
circuit is integrated with a touch pad, have been put into
practical use.
[0007] As a touch pad with an antenna of the related art, a touch
pad module (touch pad with an antenna) according to Japanese
Unexamined Patent Application Publication (Translation of PCT
Application) No. 2002-539517 has been proposed. FIGS. 11A and 11B
are explanatory diagrams illustrating the configuration of a touch
pad module 200 according to Japanese Unexamined Patent Application
Publication (Translation of PCT Application) No. 2002-539517. FIG.
11A is an explanatory diagram schematically illustrating the side
cross-section of the touch pad module 200. FIG. 11B is an
explanatory diagram schematically illustrating the lower surface of
a printed circuit board 220 used in the touch pad module 200.
[0008] The touch pad module 200 is a capacitive (electrostatic
capacitance type) touch pad. As illustrated in FIGS. 11A and 11B,
the touch pad module 200 includes the printed circuit board 220
having a nearly rectangular-shaped plate surface, and a touch
sensor array 222 including a plurality of layers formed in the
upper portion of the printed circuit board 220.
[0009] In a portion situated nearer to the center of a lower
surface 224 serving as one plate surface of the printed circuit
board 220, a chip 226, a chip 228, a configuration element 230, a
configuration element 232, a configuration element 234, and so
forth are mounted, and configure a circuit unit having a
predetermined function. The circuit unit is connected to the touch
sensor array 222 through wiring lines not illustrated. In addition,
in the outer periphery portion of the lower surface 224 of the
printed circuit board 220, an antenna 236 for wireless
communication is formed. The antenna 236 is extended along the
outer circumference of the lower surface 224 of the printed circuit
board 220.
[0010] Note that while the detailed structure of the touch sensor
array 222 is not disclosed in Japanese Unexamined Patent
Application Publication (Translation of PCT Application) No.
2002-539517, usually the touch sensor array of the capacitive touch
pad includes a first electrode group extended in the long-side
direction of a board having a nearly rectangular-shaped plate
surface, and a second electrode group extended in the short-side
direction thereof. In addition, based on a change in electrostatic
capacitance detected using the first electrode group and the second
electrode group, the position of an operation body in contact with
or close to the operation surface of the touch pad is detected.
[0011] In the touch pad module 200 according to Japanese Unexamined
Patent Application Publication (Translation of PCT Application) No.
2002-539517, the antenna 236 is extended along the outer
circumference of the nearly rectangular-shaped plate surface of the
printed circuit board 220. In addition, as described above, usually
the touch sensor array of the capacitive touch pad includes the
first electrode group extended in the long-side direction of the
board having the nearly rectangular-shaped plate surface, and the
second electrode group extended in the short-side direction
thereof. Therefore, a large portion of the antenna 236 in the
extension direction thereof is headed in a direction parallel to
the extension direction of the first electrode group or the second
electrode group.
[0012] In a point at which the extension direction of the antenna
236 is parallel to the extension direction of the first electrode
group or the second electrode group, magnetic field coupling caused
by mutual induction is easily produced between the antenna 236 and
the first electrode group or the second electrode group. In
addition, by magnetic field coupling between the antenna 236 and
the first electrode group or the second electrode group, a magnetic
field generated by the antenna 236 is easily transmitted, as a
noise, to the first electrode group or the second electrode group.
As a result, in such a structure as the touch pad module 200
according to Japanese Unexamined Patent Application Publication
(Translation of PCT Application) No. 2002-539517, there has been a
possibility that, under the influence of the noise due to the
antenna 236, detection accuracy at the time of detecting the
position of an operation body in contact with or close to an
operation surface is reduced.
[0013] The present invention is made in view of such a situation of
the related art, and provides a touch pad with an antenna, capable
of reducing the influence of a noise due to the antenna.
SUMMARY
[0014] According to a first aspect of the present invention, a
touch pad with an antenna includes a substrate on an upper side of
having set thereon an operation surface having a predetermined
operation region, an electrode group that detects capacitance
arranged in a region of the substrate corresponding to the
operation region, and an antenna for wireless communication
arranged in a region located on a lower side of the substrate, the
region overlapping with an electrode group forming region in which
the electrode group for detecting capacitance is disposed, as
viewed from above, wherein the electrode group for detecting
capacitance includes a first electrode group extended in a
predetermined first direction and a second electrode group extended
in a second direction perpendicular to the first direction, and the
antenna is extended in a direction intersecting with the first
direction and the second direction.
[0015] In the touch pad with an antenna having this configuration,
the first electrode group is extended in the first direction, and
the antenna is extended in the direction intersecting with (a
direction not parallel to) the first direction. Therefore, it is
possible to suppress magnetic field coupling due to mutual
induction between the antenna and the first electrode group. In
addition, it is possible to inhibit a magnetic field generated by
the antenna from being transmitted, as a noise, to the first
electrode group. In addition, the second electrode group is
extended in the second direction, and the antenna is extended in
the direction intersecting with (a direction not parallel to) the
second direction. Therefore, it is possible to suppress magnetic
field coupling due to mutual induction between the antenna and the
second electrode group. In addition, it is possible to inhibit the
magnetic field generated by the antenna from being transmitted, as
a noise, to the second electrode group. As a result, the touch pad
with an antenna having this configuration is able to reduce the
influence of a noise due to the antenna.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIGS. 1A and 1B are explanatory diagrams illustrating a
configuration of a touch pad according to a first embodiment of the
present invention;
[0017] FIG. 2 is an explanatory diagram illustrating a usage
example of the touch pad illustrated in FIGS. 1A and 1B;
[0018] FIG. 3 is an exploded perspective view of the touch pad
illustrated in FIGS. 1A and 1B;
[0019] FIGS. 4A and 4B are first explanatory diagrams illustrating
electrode geometries of a substrate illustrated in FIGS. 1A and
1B;
[0020] FIGS. 5A and 5B are second explanatory diagrams illustrating
electrode geometries of the substrate illustrated in FIGS. 1A and
1B;
[0021] FIGS. 6A and 6B are explanatory diagrams illustrating a
function of an antenna illustrated in FIG. 3;
[0022] FIG. 7 is an explanatory diagram illustrating a function of
a ground electrode illustrated in FIG. 3;
[0023] FIGS. 8A and 8B are explanatory diagrams illustrating a
configuration of a touch pad according to a second embodiment of
the present invention;
[0024] FIGS. 9A and 9B are first explanatory diagrams illustrating
electrode geometries of a substrate illustrated in FIGS. 8A and
8B;
[0025] FIGS. 10A and 10B are second explanatory diagrams
illustrating electrode geometries of the substrate illustrated in
FIGS. 8A and 8B; and
[0026] FIGS. 11A and 11B are explanatory diagrams illustrating a
configuration of a touch pad module according to Japanese
Unexamined Patent Application Publication (Translation of PCT
Application) No. 2002-539517.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
First Embodiment
[0027] Hereinafter, a first embodiment of the present invention
will be described with reference to drawings. Note that it is
assumed that, in each drawing, an X1 direction is a left direction,
an X2 direction is a right direction, a Y1 direction is an anterior
direction, a Y2 direction is a posterior direction, a Z1 direction
is an upper direction, and a Z2 direction is a lower direction and
an explanation will be made.
[0028] First, the configuration of a touch pad 1 (a touch pad with
an antenna) according to the first embodiment of the present
invention will be described using FIG. 1A to FIG. 5B. FIGS. 1A and
1B are explanatory diagrams illustrating the configuration of the
touch pad 1 according to the first embodiment of the present
invention. FIG. 2 is an explanatory diagram illustrating a usage
example of the touch pad 1 illustrated in FIGS. 1A and 1B. FIG. 3
is the exploded perspective view of the touch pad 1 illustrated in
FIGS. 1A and 1B. FIGS. 4A and 4B are first explanatory diagrams
illustrating the electrode geometries of a substrate 20 illustrated
in FIGS. 1A and 1B. FIG. 4A is an explanatory diagram illustrating
the electrode geometry of a first electrode group 25, and FIG. 4B
is an explanatory diagram illustrating the electrode geometry of a
second electrode group 26. FIGS. 5A and 5B are second explanatory
diagrams illustrating the electrode geometries of the substrate 20
illustrated in FIGS. 1A and 1B. FIG. 5A is an explanatory diagram
illustrating the electrode geometry of a ground electrode 27, and
FIG. 5B is an explanatory diagram illustrating the electrode
geometry of an antenna 28.
[0029] The touch pad 1 is a touch pad of a type called an
electrostatic capacitance type. As illustrated in FIGS. 1A and 1B,
the touch pad 1 includes an operation plate 10 with an operation
surface 11 on the upper side thereof, and the substrate 20 arranged
on the lower side of the operation plate 10. In addition, the touch
pad 1 is able to detect the position of an operation body such as a
fingertip in contact with or close to the operation surface 11. As
illustrated in FIG. 2, such a touch pad 1 is attached to a
predetermined location (a palm rest or the like) of a chassis 51 of
an electronic device 50 such as a notebook computer so that the
operation surface 11 is exposed, and the touch pad 1 is used for
moving a cursor of a screen, or the like.
[0030] The operation plate 10 is a plate-like member made of a
synthetic resin, and includes nearly rectangular-shaped plate
surfaces on the top and bottom thereof. As illustrated in FIG. 3,
the top surface of the operation plate 10 is the operation surface
11, and a predetermined region of the operation surface 11 is an
operation region 11a. In the present embodiment, the operation
region 1 1a is a square-shaped region having sides extending in a
first direction on the operation surface 11 and a second direction
perpendicular to the first direction. As illustrated in FIG. 3, the
first direction is a horizontal direction, and the second direction
is a front-back direction.
[0031] The substrate 20 is a multilayer substrate made of a
synthetic resin, and includes nearly rectangular-shaped plate
surfaces on the top and bottom thereof. As illustrated in FIG. 3,
the substrate 20 includes four electrode forming layers of a first
electrode forming layer 21, a second electrode forming layer 22, a
ground electrode forming layer 23, and an antenna forming layer 24.
Predetermined electrodes made of a conductive material such as
copper are formed in the first electrode forming layer 21, the
second electrode forming layer 22, the ground electrode forming
layer 23, and the antenna forming layer 24.
[0032] The first electrode forming layer 21, the second electrode
forming layer 22, the ground electrode forming layer 23, and the
antenna forming layer 24 are stacked with sandwiching therebetween
insulation layers not illustrated, in the order of the first
electrode forming layer 21, the second electrode forming layer 22,
the ground electrode forming layer 23, and the antenna forming
layer 24 starting from the top. In addition, the first electrode
forming layer 21 is the top surface of the substrate 20, and the
antenna forming layer 24 is the bottom surface of the substrate 20.
The upper side of the first electrode forming layer 21 and the
lower side of the antenna forming layer 24 are covered by
insulating coatings not illustrated.
[0033] In the first electrode forming layer 21 of the substrate 20,
the first electrode group 25 serving as a first electrode group for
detecting capacitance is formed. The first electrode group 25 is
formed in the inside of a first electrode forming region 21a
serving as a square-shaped region overlapping with the operation
region 11a as viewed from above. The first electrode group 25
includes a plurality of first electrodes 25a. As illustrated in
FIGS. 4A and 4B, each of the first electrodes 25a is a nearly
rectangular-shaped electrode extended in the first direction. The
first electrodes 25a may be arranged so as to be placed at regular
intervals in the second direction. Note that, in the present
embodiment, the first electrodes 25a of the first electrode group
25 are used as drive electrodes, and an electric signal for driving
is applied to each of the first electrodes 25a.
[0034] In the second electrode forming layer 22 of the substrate
20, the second electrode group 26 serving as a second electrode
group for detecting capacitance is formed. The second electrode
group 26 is formed in the inside of a second electrode forming
region 22a serving as a square-shaped region overlapping with the
operation region 11a as viewed from above. The second electrode
group 26 includes a plurality of second electrodes 26a. As
illustrated in FIGS. 4A and 4B, each of the second electrodes 26a
is a nearly rectangular-shaped electrode extended in the second
direction. The second electrodes 26a may be arranged so as to be
placed at regular intervals in the first direction. Note that, in
the present embodiment, the second electrodes 26a of the second
electrode group 26 are used as detection electrodes.
[0035] The first electrodes 25a of the first electrode group 25 and
the second electrodes 26a of the second electrode group 26 are
arranged so as to intersect with each other as viewed from above.
In addition, one of the first electrodes 25a and a corresponding
one of the second electrodes 26a form electrostatic capacitance in
the vicinity of a position at which one of the first electrodes 25a
and the corresponding one of the second electrodes 26a intersect
with each other. In addition, by the electrostatic capacitance
between one of the first electrodes 25a and the corresponding one
of the second electrodes 26a, the electric signal for driving
applied to one of the first electrodes 25a is transmitted from one
of the first electrodes 25a to the corresponding one of the
corresponding second electrodes 26a. In the touch pad 1, based on a
change in the electric signal transmitted from one of the first
electrodes 25a to the corresponding one of the corresponding second
electrodes 26a in this way, it is possible to detect a change in
the electrostatic capacitance between one of the first electrodes
25a and the corresponding one of the second electrodes 26a.
[0036] The ground electrode 27 is formed in the ground electrode
forming layer 23 of the substrate 20. The ground electrode 27 may
be formed in the inside of a ground electrode forming region 23a
serving as a square-shaped region overlapping with the whole
regions of the first electrode forming region 21a and the second
electrode forming region 22a as viewed from above.
[0037] As illustrated in FIGS. 5A and 5B, the ground electrode 27
may be formed by adding a plurality of slits 27a to a square-shaped
electrode covering the whole region of the ground electrode forming
region 23a. The slits 27a may be arranged at regular intervals in a
rotation direction centered at the central portion of the ground
electrode 27. In addition, the slits 27a may each radially extend
from the vicinity of the central portion of the ground electrode 27
to the outer periphery portion thereof. The outer periphery portion
of the ground electrode 27 may be divided into a plurality of
ground electrode patterns 27b by the slits 27a. The central portion
of the ground electrode 27 may be a linking portion 27c linking the
ground electrode patterns 27b divided by the slits 27a.
[0038] In the antenna forming layer 24 of the substrate 20, an
electrode pattern to serve as the antenna 28 for wireless
communication is formed. Hereinafter, the electrode pattern to
serve as the antenna 28 for wireless communication is abbreviated
as the antenna 28. The antenna 28 is formed in the inside of an
antenna forming region 24a serving as a square-shaped region
overlapping with the first electrode forming region 21a and the
second electrode forming region 22a as viewed from above.
[0039] As illustrated in FIGS. 5A and 5B, the antenna 28 may be a
coiled (spiral-coil-shaped) antenna wound along the outer
circumference of a circle sharing the center thereof with the
antenna forming region 24a. Two end portions of the antenna 28 are
terminal portions 28a connected to a circuit.
[0040] A region on the left side of the antenna forming region 24a
and a region on the right side thereof in the antenna forming layer
24 are circuit forming regions 24b in which predetermined circuits
are formed. In the circuit forming regions 24b, various kinds of
electronic components not illustrated are mounted and a detection
circuit 30 for detecting the position of the operation body in
contact with or close to the operation surface 11, a communication
circuit 40 for wireless communication, and so forth are formed.
[0041] The detection circuit 30 is connected to the first electrode
group 25 and the second electrode group 26, described above,
through electrodes for wiring lines, not illustrated. The detection
circuit 30 applies an electric signal for driving to each of the
first electrodes 25a of the first electrode group 25, detects an
electric signal transmitted to a corresponding one of the second
electrodes 26a of the second electrode groups 26, and detects,
based on a change in an electric signal transmitted from one of the
first electrodes 25a to a corresponding one of the second
electrodes 26a, a change in electrostatic capacitance between one
of the first electrodes 25a and the corresponding one of the second
electrodes 26a. In addition, based on a change in the electrostatic
capacitance detected using the first electrode group 25 and the
second electrode group 26, the detection circuit 30 detects the
position of the operation body in contact with or close to the
operation surface 11 of the touch pad 1. Note that since the
circuit configuration and so forth of such a detection circuit 30
are publicly known, the detailed descriptions thereof will be
omitted.
[0042] The communication circuit 40 is a communication circuit
compatible with the standard of short distance wireless
communication. The communication circuit 40 is connected to the
terminal portions 28a of the antenna 28 through electrodes for
wiring lines not illustrated. In addition, the communication
circuit 40 applies an electric signal for wireless communication to
the terminal portions 28a of the antenna 28. Note that since the
circuit configuration of such a communication circuit 40 is
publicly known, the detailed description thereof will be
omitted.
[0043] The substrate 20 has such a configuration as described
above. In addition, the operation plate 10 is stuck on the upper
side of such a substrate 20 using an adhesive or the like. As a
result, the operation surface 11 having the predetermined operation
region 11a is set on the upper side of the substrate 20.
[0044] Next, the function of the antenna 28 will be described using
FIGS. 6A and 6B. FIGS. 6A and 6B are explanatory diagrams
illustrating the function of the antenna 28 illustrated in FIG. 3.
FIG. 6A is an explanatory diagram schematically illustrating the
radiation direction Ra of a magnetic flux generated by the antenna
28 in a case of viewing the antenna 28 from above along with the
first electrode group 25. FIG. 6B is an explanatory diagram
schematically illustrating the radiation direction Ra of the
magnetic flux generated by the antenna 28 in a case of viewing the
antenna 28 from above along with the second electrode group 26.
[0045] When the electric signal for wireless communication is
applied to the terminal portions 28a of the antenna 28, a current
corresponding to the applied electric signal flows through the
antenna 28, and a magnetic flux is generated in a direction
perpendicular to the current flowing through the antenna 28. In
addition, in response to the magnetic flux generated by the antenna
28, a magnetic field is formed around the antenna 28. In FIGS. 6A
and 6B, the magnetic flux generated by the antenna 28 is radiated
in a direction from the center of the antenna forming region 24a
toward the outer side portion thereof. In addition, a magnetic
field distribution approximately rotationally symmetrical to the
center of the antenna forming region 24a is formed. Using the
magnetic field formed in this way, the antenna 28 performs
transmission and reception of signals to and from an external
communication device not illustrated.
[0046] Note that, as will be appreciated from the above-mentioned
configuration of the touch pad 1, the first electrode group 25 is
arranged on the upper side of the antenna 28. The first electrodes
25a of the first electrode group 25 are extended in the first
direction, as illustrated in FIG. 6A. In a case where the antenna
28 is extended in, for example, the first direction (a direction
parallel to the extension direction of the first electrodes 25a)
with respect to such first electrodes 25a, magnetic field coupling
due to mutual induction is easily produced between the antenna 28
and a corresponding one of the first electrodes 25a at a point at
which the extension direction of the antenna 28 and the extension
direction of the corresponding one of the first electrodes 25a are
parallel to each other. The strength of the magnetic field coupling
between the antenna 28 and the corresponding one of the first
electrodes 25a increases with an increase in the length of the
point at which the extension direction of the antenna 28 and the
extension direction of the corresponding one of the first
electrodes 25a are parallel to each other.
[0047] In addition, by the magnetic field coupling between the
antenna 28 and the corresponding one of the first electrodes 25a, a
magnetic field generated by the antenna 28 is caused to be easily
transmitted to the corresponding one of the first electrodes 25a,
as a noise. As a result, there is a possibility that, under the
influence of the noise due to the antenna 28, detection accuracy at
the time of detecting the position of the operation body in contact
with or close to the operation surface is reduced.
[0048] However, the antenna 28 may be a coiled antenna wound along
the outer circumference of a circle sharing the center thereof with
the antenna forming region 24a, and there is hardly a point at
which the extension direction of the antenna 28 and the extension
direction of a corresponding one of the first electrodes 25a are
parallel to each other. Therefore, it is possible to suppress
magnetic field coupling due to mutual induction between the antenna
28 and the first electrodes 25a. In addition, it is possible to
inhibit the magnetic field generated by the antenna 28 from being
transmitted to the first electrodes 25a, as a noise.
[0049] In addition, as will be appreciated from the above-mentioned
configuration of the touch pad 1, the second electrode group 26 is
arranged on the upper side of the antenna 28. The second electrodes
26a of the second electrode group 26 are extended in the second
direction, as illustrated in FIG. 6B. In a case where the antenna
28 is extended in, for example, the second direction (a direction
parallel to the extension direction of the second electrodes 26a)
with respect to such second electrodes 26a, magnetic field coupling
due to mutual induction is easily produced between the antenna 28
and a corresponding one of the second electrodes 26a at a point at
which the extension direction of the antenna 28 and the extension
direction of the corresponding one of the second electrodes 26a are
parallel to each other. In addition, by the magnetic field coupling
between the antenna 28 and the corresponding one of the second
electrodes 26a, a magnetic field generated by the antenna 28 is
caused to be easily transmitted to the corresponding one of the
second electrodes 26a, as a noise.
[0050] However, the antenna 28 may be a coiled antenna wound along
the outer circumference of a circle sharing the center thereof with
the antenna forming region 24a, and there is hardly a point at
which the extension direction of the antenna 28 and the extension
direction of a corresponding one of the second electrodes 26a are
parallel to each other. Therefore, it is possible to suppress
magnetic field coupling due to mutual induction between the antenna
28 and the second electrodes 26a. In addition, it is possible to
inhibit the magnetic field generated by the antenna 28 from being
transmitted to the second electrodes 26a, as a noise.
[0051] Note that the antenna 28 may be a coiled antenna wound along
the outer circumference of a circle. Therefore, strictly speaking,
in the vicinity of the anterior end portion of the antenna 28 and
in the vicinity of the posterior end portion thereof, there are
points at which the extension direction of the antenna 28 and the
extension direction of the first electrodes 25a are parallel to
each other. However, since such points each have no sufficient
length, it is possible to regard the antenna 28 as a coil extended
in a direction intersecting with the extension direction of the
first electrodes 25a.
[0052] In addition, in the same way, in the vicinity of the left
end portion of the antenna 28 and in the vicinity of the right end
portion thereof, there are points at which the extension direction
of the antenna 28 and the extension direction of the second
electrodes 26a are parallel to each other. However, since such
points each have no sufficient length, it is possible to regard the
antenna 28 as a coil extended in a direction intersecting with the
extension direction of the second electrodes 26a.
[0053] Next, using FIG. 7, the function of the ground electrode 27
will be described. FIG. 7 is an explanatory diagram illustrating
the function of the ground electrode 27 illustrated in FIG. 3. FIG.
7 is an explanatory diagram schematically illustrating the
radiation direction Ra of the magnetic flux generated by the
antenna 28 in a case of viewing the antenna 28 from above along
with the ground electrode 27.
[0054] As will be appreciated from the above-mentioned
configuration of the touch pad 1, the ground electrode 27 may be
arranged at a position, located on the lower side of the first
electrode group 25 and the second electrode group 26 and located on
the upper side of the antenna 28. In addition, the ground electrode
27 inhibits an electromagnetic wave noise generated by the main
body of the electronic device 50 from being radiated to the outside
of the electronic device 50, and inhibits the magnetic field
generated by the antenna 28 from being transmitted, as a noise, to
the first electrode group 25 and the second electrode group 26.
[0055] In addition, as illustrated in FIG. 7, the slits 27a may be
formed in the ground electrode 27. In addition, a signal for
wireless communication is radiated from the antenna 28 to the
outside of the electronic device 50 through the slits 27a.
Furthermore, the slits 27a may be arranged at regular intervals in
the rotation direction centered at the center of the ground
electrode 27. In addition, the bias of the signal with respect to
the rotation direction centered at the center of the ground
electrode 27 is reduced, the signal being radiated from the antenna
28 to the outside of the electronic device 50 through the slits
27a.
[0056] In addition, the slits 27a have a function for suppressing
an eddy current flowing through the ground electrode 27. In
general, in a case where the ground electrode 27 is arranged on the
upper side of such a coiled antenna as the antenna 28, an eddy
current flows through the ground electrode 27 in the extension
direction of the antenna 28 in response to the magnetic field
generated by the antenna 28. In addition, in connection with the
eddy current flowing through the ground electrode 27, the loss of
electric power is generated. In contrast, as illustrated in FIG. 7,
in the present embodiment, the slits 27a may be formed so as to
radially extend from the vicinity of the central portion of the
ground electrode 27, and such slits 27a suppress the eddy current
flowing through the ground electrode 27 in response to the magnetic
field generated by the antenna 28.
[0057] Note that the slits 27a may divide the outer periphery
portion of the ground electrode 27 into the ground electrode
patterns 27b. Usually, the antenna 28 is formed in the vicinity of
the outer periphery portion of the antenna forming region 24a.
Therefore, the strength of the magnetic field generated by the
antenna 28 increases in the vicinity of the outer periphery portion
of the antenna forming region 24a, compared with the vicinity of
the central portion of the antenna forming region 24a. In response
to that, the magnitude of an eddy current flowing through the
vicinity of the outer periphery portion of the ground electrode 27
becomes larger than that of an eddy current flowing through the
vicinity of the central portion thereof. In addition, compared with
the path of the eddy current flowing through the vicinity of the
central portion of the ground electrode 27, the path of the eddy
current flowing through the vicinity of the outer periphery portion
of the ground electrode 27 is long. Therefore, compared with a loss
due to the eddy current flowing through the vicinity of the central
portion of the ground electrode 27, a loss due to the eddy current
flowing through the vicinity of the outer periphery portion thereof
becomes large. Therefore, in a case of forming the slits 27a, a
case of forming the slits 27a so as to divide the outer periphery
portion of the ground electrode 27 obtains a great advantageous
effect compared with a case of forming the slits 27a so as to
divide the central portion of the ground electrode 27.
[0058] Next, advantageous effects of the present embodiment will be
described. In the touch pad 1 of the present embodiment, the first
electrodes 25a of the first electrode group 25 are extended in the
first direction (horizontal direction), and the antenna 28 is
extended in a direction intersecting with (a direction not parallel
to) the first direction. Therefore, it is possible to suppress
magnetic field coupling due to mutual induction between the antenna
28 and the first electrodes 25a of the first electrode group 25. In
addition, it is possible to inhibit the magnetic field generated by
the antenna 28 from being transmitted, as a noise, to the first
electrodes 25a of the first electrode group 25. In addition, the
second electrodes 26a of the second electrode group 26 are extended
in the second direction (front-back direction), and the antenna 28
is extended in a direction intersecting with (a direction not
parallel to) the second direction. Therefore, it is possible to
suppress magnetic field coupling due to mutual induction between
the antenna 28 and the second electrodes 26a of the second
electrode group 26. In addition, it is possible to inhibit the
magnetic field generated by the antenna 28 from being transmitted,
as a noise, to the second electrodes 26a of the second electrode
group 26. As a result, the touch pad 1 of this configuration is
able to reduce the influence of a noise due to the antenna 28.
[0059] In addition, in the touch pad 1 of the present embodiment,
the antenna 28 may be a coiled antenna wound along the outer
circumference of a circle. Therefore, the antenna 28 is able to
form a magnetic field approximately rotationally symmetrical to the
center of the circle. As a result, it is possible to reduce the
bias of a communication sensitivity with respect to a communication
direction. In particular, the shape of such an antenna 28 is
effective for a touch pad having a square-shaped operation
region.
[0060] In addition, in the touch pad 1 of the present embodiment,
using the ground electrode 27 arranged at a position, located on
the lower side of the first electrode group 25 and the second
electrode group 26 and located on the upper side of the antenna 28,
it is possible to inhibit the electromagnetic wave noise generated
by the main body of the electronic device 50 from being radiated to
the outside of the electronic device 50, and it is possible to
further inhibit the magnetic field generated by the antenna 28 from
being transmitted, as a noise, to the first electrode group 25 and
the second electrode group 26. Furthermore, since the slits 27a may
be formed in the ground electrode 27, it is possible to radiate the
signal for wireless communication from the antenna 28 to the
outside of the electronic device 50 through the slits 27a. In
addition, since the slits 27a may radially extend from the vicinity
of the central portion of the ground electrode 27, it is possible
to suppress the eddy current flowing through the ground electrode
27 in response to the magnetic field generated by the antenna 28.
In addition, it is possible to reduce a loss associated with the
eddy current.
[0061] In addition, in the touch pad 1 of the present embodiment,
the slits 27a may be arranged at regular intervals in the rotation
direction centered at the center of the ground electrode 27.
Therefore, it is possible to reduce the bias of a signal with
respect to the rotation direction centered at the center of the
ground electrode 27, the signal being radiated from the antenna 28
to the outside of the electronic device 50 through the slits
27a.
[0062] In addition, in the touch pad 1 of the present embodiment,
the slits 27a may be formed so as to divide the outer periphery
portion of the ground electrode 27. Therefore, it is possible to
prevent the eddy current from flowing through the vicinity of the
outer periphery portion of the ground electrode 27. As a result, it
is possible to further suppress the eddy current flowing through
the ground electrode 27 in response to the magnetic field generated
by the antenna 28. In addition, it is possible to further reduce a
loss associated with the eddy current.
[0063] In addition, while, in the touch pad 1 of the present
embodiment, the outer periphery portion of the ground electrode 27
may be divided by the slits 27a into the ground electrode patterns
27b, it is possible to electrically connect the ground electrode
patterns 27b using the linking portion 27c. Therefore, it is
possible to reduce the number of ground wiring lines connected to
the ground electrode 27, compared with a case where the ground
electrode patterns 27b are not linked to the linking portion 27c.
As a result, it is possible to simplify the structure of the touch
pad 1.
Second Embodiment
[0064] Hereinafter, a second embodiment of the present invention
will be described with reference to drawings. Note that, in the
present embodiment, in a case of the same configuration as that of
the above-mentioned first embodiment, a same symbol is assigned
thereto and the detailed description thereof will be omitted.
[0065] First, the configuration of a touch pad 101 (a touch pad
with an antenna) according to the second embodiment of the present
invention will be described using FIG. 8A to FIG. 10B. FIGS. 8A and
8B are explanatory diagrams illustrating the configuration of the
touch pad 101 according to the second embodiment of the present
invention. FIGS. 9A and 9B are first explanatory diagrams
illustrating the electrode geometries of a substrate 120
illustrated in FIGS. 8A and 8B. FIG. 9A is an explanatory diagram
illustrating the electrode geometry of the first electrode group
25, and FIG. 9B is an explanatory diagram illustrating the
electrode geometry of the second electrode group 26. FIGS. 10A and
10B are second explanatory diagrams illustrating the electrode
geometries of the substrate 120 illustrated in FIGS. 8A and 8B.
FIG. 10A is an explanatory diagram illustrating the electrode
geometry of the ground electrode 27, and FIG. 10B is an explanatory
diagram illustrating the electrode geometry of an antenna 128.
[0066] In the same way as the touch pad 1 of the first embodiment,
the touch pad 101 is a touch pad of a type called an electrostatic
capacitance type. As illustrated in FIGS. 8A and 8B, the touch pad
101 includes an operation plate 110, and the substrate 120 arranged
on the lower side of the operation plate 110. In addition, the top
surface of the operation plate 110 is the operation surface 11, and
a predetermined region of the operation surface 11 is the operation
region 11a. In this regard, however, in the present embodiment, the
operation region 11a may be a rectangular-shaped region having long
sides extending in the first direction on the operation surface 11
and short sides extending in the second direction perpendicular to
the first direction. While not illustrated, the substrate 120
includes four electrode forming layers of the first electrode
forming layer 21, the second electrode forming layer 22, the ground
electrode forming layer 23, and the antenna forming layer 24, in
the same way as the substrate 20 of the first embodiment.
[0067] In the first electrode forming layer 21 of the substrate
120, the first electrode group 25 is formed in the same way as the
first embodiment. In this regard, however, as illustrated in FIGS.
9A and 9B, the first electrode forming region 21a of the first
electrode forming layer 21 is a rectangular-shaped region
overlapping with the operation region 11a as viewed from above. In
the second electrode forming layer 22 of the substrate 120, the
second electrode group 26 is formed in the same way as the first
embodiment. In this regard, however, as illustrated in FIGS. 9A and
9B, the second electrode forming region 22a of the second electrode
forming layer 22 is a rectangular-shaped region overlapping with
the operation region 11a as viewed from above.
[0068] In the ground electrode forming layer 23 of the substrate
120, the ground electrode 27 is formed in the same way as the first
embodiment. In this regard, however, as illustrated in FIGS. 10A
and 10B, the ground electrode forming region 23a of the ground
electrode forming layer 23 is a rectangular-shaped region
overlapping the whole regions of the first electrode forming region
21a and the second electrode forming region 22a as viewed from
above. In addition, the ground electrode 27 may be formed by adding
the slits 27a to a nearly rectangular-shaped electrode covering the
whole region of the ground electrode forming region 23a.
[0069] In the antenna forming layer 24 of the substrate 120, not
the antenna 28 but the antenna 128 is formed as illustrated in
FIGS. 10A and 10B. In addition, the antenna forming region 24a of
the antenna forming layer 24 is a rectangular-shaped region
overlapping with the first electrode forming region 21a and the
second electrode forming region 22a as viewed from above. The
antenna 128 may be a coiled (spiral-coil-shaped) antenna wound
along the outer circumference of an ellipse having a long axis
extending in the first direction and a short axis extending in the
second direction. The outside dimension of the antenna 128 is set
so that distances from the outer periphery portion of the operation
region 11a to the antenna 128 in a long-side direction and a
short-side direction become approximately equal to each other. Two
end portions of the antenna 128 are terminal portions 128a
connected to a circuit.
[0070] Next, advantageous effects of the present embodiment will be
described. In the touch pad 101 of the present embodiment, the
first electrodes 25a of the first electrode group 25 are extended
in the first direction (horizontal direction), and the antenna 128
is extended in a direction intersecting with (a direction not
parallel to) the first direction. Therefore, it is possible to
suppress magnetic field coupling due to mutual induction between
the antenna 128 and the first electrodes 25a of the first electrode
group 25. In addition, it is possible to inhibit a magnetic field
generated by the antenna 128 from being transmitted, as a noise, to
the first electrodes 25a of the first electrode group 25. In
addition, the second electrodes 26a of the second electrode group.
26 are extended in the second direction (front-back direction), and
the antenna 128 is extended in a direction intersecting with (a
direction not parallel to) the second direction. Therefore, it is
possible to suppress magnetic field coupling due to mutual
induction between the antenna 128 and the second electrodes 26a of
the second electrode group 26. In addition, it is possible to
inhibit the magnetic field generated by the antenna 128 from being
transmitted, as a noise, to the second electrodes 26a of the second
electrode group 26. As a result, the touch pad 101 of this
configuration is able to reduce the influence of a noise due to the
antenna 128.
[0071] In addition, depending on the application or standard of the
electronic device 50, there is a case where a touch pad having not
a square-shaped operation region but a rectangular-shaped operation
region in such a manner as the touch pad 101 is used. In a case
where, with respect to such a touch pad, the antenna 128 is, for
example, a coiled antenna wound along the outer circumference of a
circle, distances from the outer periphery portion of the operation
region 11a to the antenna 128 in the long-side direction and the
short-side direction are different from each other. As a result,
there is a possibility that the bias of the communication
sensitivity with respect to the communication direction is produced
even if distances from the outer periphery portion of the operation
region 11a are equal to each other.
[0072] However, in the touch pad 101 of the present embodiment, the
operation region 11a may be the rectangular-shaped region having
the long sides extending in the first direction (horizontal
direction) and the short sides extending in the second direction
(front-back direction), and the antenna 128 may be the coiled
antenna wound along the outer circumference of the ellipse having
the long axis extending in the first direction and the short axis
extending in the second direction. Therefore, compared with a case
where the antenna 128 is the coiled antenna wound along the outer
circumference of a circle, it is possible to reduce the bias of a
distance from the outer periphery portion of the operation region
11a to the antenna 128. As a result, even in a case of a touch pad
having the rectangular-shaped operation region 11a in such a manner
as the touch pad 101, it is possible to reduce the bias of the
communication sensitivity with respect to the communication
direction.
[0073] While embodiments of the present invention are described as
above, the present invention is not limited to the above-mentioned
embodiments, and may be arbitrarily modified without departing from
the scope of purposes of the present invention.
[0074] For example, in an embodiment of the present invention, an
electronic device to which the touch pad 1 (or the touch pad 101)
is to be attached may be a device other than the notebook computer.
The touch pad 1 (or the touch pad 101) may be used as an input
device such as, for example, a game machine or an in-vehicle
navigation device.
[0075] In addition, in an embodiment of the present invention, the
touch pad 1 (or the touch pad 101) may include a member other than
the above-mentioned members. The touch pad 1 (or the touch pad 101)
may include, for example, a supporting member for swingably
attaching itself to an electronic device. In addition, a push
switch or the like for detecting the swinging operation of the
touch pad 1 (or the touch pad 101) may be attached to the bottom
surface of the substrate 20 (or the substrate 120). In addition,
the touch pad 1 (or the touch pad 101) may include an attaching
structure for attaching itself to the chassis of the electronic
device 50.
[0076] In addition, in an embodiment of the present invention, the
operation region 11a may have a shape other than the
above-mentioned shapes. A corner portion of the square shape (or
the rectangular shape) of the operation region 11a may have, for
example, a circular arc shape. In addition, if it is possible to
detect the position of the operation body in contact with or close
to the operation surface 11 with predetermined accuracy, the
operation region 11a may be a circular-shaped or elliptical-shaped
region.
[0077] In addition, in an embodiment of the present invention, the
substrate 20 (or the substrate 120) is allowed not to include the
circuit forming region 24b, and the touch pad 1 (or the touch pad
101) is allowed not to include the detection circuit 30 or the
communication circuit 40. In addition, the first electrode group 25
and the second electrode group 26 may be connected to, for example,
a detection circuit and a communication circuit, formed on the main
body side of the electronic device 50, through wiring lines or the
like.
[0078] In addition, in an embodiment of the present invention, the
first electrodes 25a of the first electrode group 25 and the second
electrodes 26a of the second electrode group 26 may each have a
shape other than a rectangular shape. The first electrodes 25a may
be electrodes in which, for example, a plurality of rhomboid-shaped
electrodes linked to each other are arranged so as to be placed
alongside each other in the first direction. In addition, the
second electrodes 26a may be electrodes in which a plurality of
rhomboid-shaped electrodes linked to each other are arranged so as
to be placed alongside each other in the second direction.
[0079] In addition, while, in the embodiments of the present
invention, the first electrodes 25a of the first electrode group 25
are used as drive electrodes and the second electrodes 26a of the
second electrode group 26 are used as detection electrodes, the
second electrodes 26a may be used as drive electrodes and the first
electrodes 25a may be used as detection electrodes. In addition, a
state in which the first electrodes 25a are used as drive
electrodes and the second electrodes 26a are used as detection
electrodes and a state in which the second electrodes 26a are used
as drive electrodes and the first electrodes 25a are used as
detection electrodes may be alternately switched depending on the
timing of detection. In addition, the touch pad 1 (or the touch pad
101) may include an electrode to serve as a detection electrode
other than the first electrodes 25a and the second electrodes 26a,
and may use the first electrodes 25a and the second electrodes 26a
as drive electrodes.
[0080] In addition, in an embodiment of the present invention, the
antenna 28 (or the antenna 128) may have a shape other than the
above-mentioned shapes. If being able to realize a predetermined
communication function, the antenna 28 (or the antenna 128) may be,
for example, a linear antenna extended in a direction intersecting
with the first direction and the second direction. In addition, the
antenna 28 (or the antenna 128) may be a coiled
(spiral-coil-shaped) antenna wound along the external form of a
rhomboid having sides extending in a direction intersecting with
the first direction and the second direction.
[0081] In addition, in an embodiment of the present invention, the
antenna 28 (or the antenna 128) may be arranged on the lower side
of the substrate 20 (or the substrate 120) after being formed in a
sheet-like member different from the substrate 20 (or the substrate
120). In addition, a magnetic sheet for suppressing the influence
of a magnetic field on the main body of the electronic device 50, a
supporting plate for supporting the touch pad 1 from below, or the
like may be arranged on the lower side of the antenna 28 (or the
antenna 128).
* * * * *